In recent years, from viewpoints of emission reduction of carbon dioxide and efficient utilization of energy, an electric motor vehicle which utilizes an electric motor (hereinafter also referred to as a “motor”) as a driving source is put into practical use. The electric motor uses electric energy charged in a storage battery (hereinafter also referred to as a “battery”) as an electric power source.
However, an energy density of the battery for the electric motor vehicle is small as compared with gasoline. Because of this, a cruising range at a full charge is as short as about 100 to 200 km. Since power is consumed by an electric load, such as an air conditioner, in the electric motor vehicle, the cruising range is further shortened.
Meanwhile, there is proposed an electric type hybrid motor vehicle (hereinafter also referred to as a “hybrid vehicle”) which utilizes both electricity and gasoline as an energy source. In the hybrid vehicle, there is proposed a technique for selecting a traveling mode for every road section in which the hybrid vehicle travels. As the traveling mode, for example, an EV mode in which only electric energy is used for driving, or an HV mode in which energy of both electricity and gasoline are used for driving is employed. Due to such a selection, a battery is charged by the electric energy obtained by traveling of the hybrid vehicle, and the electric energy charged in the battery is efficiently utilized.
For example, in Patent Document 1 described below, a technique for obtaining information about traveling energy consumed when a vehicle has actually traveled in every road section and about regenerative energy (in Patent Document 1, energy charged to a battery by AC power generated by a motor by resistance force during deceleration) and for storing the information in a recording medium as history data is disclosed. Also, calculation of a difference between an average value or a maximum value of the traveling energy in a case where the vehicle has traveled in the same road section for a plurality of times and an average value or a minimum value of the regenerative energy is performed tracing back an estimated route from a departure place to a destination. With this configuration, a section in which the vehicle can travel up to the destination in an EV mode (an “EV finish section”) is determined.
In Patent Document 1, employment of an HV mode in a section other than the EV finish section is proposed. For example, a rechargeable point serves as a destination point, a section which employs the HV mode is disposed before the EV finish section. Also, when the vehicle arrives at the destination point, control is performed so that a residual quantity of the battery is set to a lower limit value.
Further, in Patent Document 1, a technique for determining a starting point of the EV finish section by learning processing which uses the history data of a travelling situation when the vehicle has traveled before in the same road section (this affects power consumption of the battery) is disclosed. With this configuration, there is proposed lowering of the battery residual quantity to the lower limit value at the destination point more accurately.
It should be noted that, in Patent Document 2, energy calculation under predetermined conditions which depend on a vehicle is described.